title: Characterization of nuclear localization signals in the type III effectors HsvG and HsvB of the gall-forming bacterium Pantoea agglomerans.
abstract: HsvG and HsvB, two paralogous type III effectors of the gall-forming bacteria Pantoea agglomerans pv. gypsophilae and P. agglomerans pv. betae, determine host specificity on gypsophila and beet, respectively. They were previously shown to be DNA-binding proteins imported into host and non-host nuclei and might act as transcriptional activators. Sequence analysis of these effectors did not detect canonical nuclear localization signals (NLSs), but two basic amino acid clusters designated putative NLS1 and NLS2 were detected in their N-terminal and C-terminal regions, respectively. pNIA assay for nuclear import in yeast and bombardment of melon leaves with each of the NLSs fused to a 2xYFP reporter indicated that putative NLS1 and NLS2 were functional in transport of HsvG into the nucleus. A yeast two-hybrid assay showed that HsvB, HsvG, putative NLS1, putative NLS2, HsvG converted into HsvB, or HsvB converted into HsvG by exchanging the repeat domain, all interacted with AtKAP-α and importin-α3 of Arabidopsis thaliana. Deletion analysis of the NLS domains in HsvG suggested that putative NLS1 or NLS2 were required for pathogenicity on gypsophila cuttings and presumably for import of HsvG into the nucleus. This study demonstrates the presence of two functional NLSs in the type III effectors HsvG and HsvB.
authors.affiliation: Department of Molecular Biology and Ecology of Plants, Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv 69978, Israel.|Department of Plant Pathology and Weed Research, ARO, The Volcani Center, Bet Dagan 50250, Israel.
authors.forename: Dan M
authors.initials: DM
authors.lastname: Weinthal
authors.affiliation: Department of Molecular Biology and Ecology of Plants, Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv 69978, Israel.
authors.forename: Isaac
authors.initials: I
authors.lastname: Barash
authors.affiliation: Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA.
authors.forename: Tzvi
authors.initials: T
authors.lastname: Tzfira
authors.affiliation: Department of Plant Pathology and Weed Research, ARO, The Volcani Center, Bet Dagan 50250, Israel.
authors.forename: Victor
authors.initials: V
authors.lastname: Gaba
authors.affiliation: Department of Molecular Biology and Ecology of Plants, Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv 69978, Israel.
authors.forename: Doron
authors.initials: D
authors.lastname: Teper
authors.affiliation: Department of Molecular Biology and Ecology of Plants, Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv 69978, Israel.
authors.forename: Guido
authors.initials: G
authors.lastname: Sessa
authors.affiliation: Department of Plant Pathology and Weed Research, ARO, The Volcani Center, Bet Dagan 50250, Israel.
authors.forename: Shulamit
authors.initials: S
authors.lastname: Manulis-Sasson
mesh_terms: D021581:Active Transport, Cell Nucleus; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D027461:Beta vulgaris / Q000382:microbiology; D029748:Caryophyllaceae / Q000382:microbiology; D002467:Cell Nucleus / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D019913:Nuclear Localization Signals; D020636:Pantoea / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity; D010941:Plant Tumors / Q000382:microbiology*; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D015534:Trans-Activators / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; C113709:HsvG protein, Pantoea agglomerans; D019913:Nuclear Localization Signals; D015534:Trans-Activators